Despite high vaccine coverage and effectiveness, the incidence of symptomatic
infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has
been increasing in Israel. Whether the increasing incidence of infection is due
to waning immunity after the receipt of two doses of the BNT162b2 vaccine is

We conducted a 6-month longitudinal prospective study involving vaccinated
health care workers who were tested monthly for the presence of anti-spike IgG
and neutralizing antibodies. Linear mixed models were used to assess the dynamics
of antibody levels and to determine predictors of antibody levels at 6 months.